The present invention relates to a breathable and waterproof sole for shoes.
Shoes having rubber soles which can ensure particular practicality and comfort but do not allow the foot to breathe at all are already known and commercially available.
Rubber soles with perforations in the tread and membranes superimposed on the perforated area and sealed in the peripheral regions have also been known for a few years.
These soles allow correct breathing in addition to an effective exchange of heat and water vapor between the environment inside the shoe and the outside environment while ensuring the necessary impermeableness to external moisture and water.
Other constructive solutions provide box-like rubber soles with perforations at the lateral edges which are internally obstructed by waterproof and breathable membranes which in this case also are joined peripherally so as to form a seal.
These perforated soles, provided with waterproof and breathable membranes, have certainly constituted considerable improvements with respect to what was previously available.
Nonetheless, there are still some practical drawbacks mainly due to the area occupied by the perforations, which though being sufficient has not yet reached its optimum extension.
On the other hand, in the first case the number of perforations formed in the tread and the diameter of said perforations must be kept small in order to prevent pointed foreign matter entering through the perforations from penetrating until they damage or pierce the membrane.
Such membrane is in fact continuously subjected to the compressive action of the foot, so that even a body which is not particularly sharp might easily cause damage.
Soles are also known which internally comprise channels and systems for pumping air from the inside of the shoe to the outside by means of one-way valves.
Pumping is actuated by the compression of the foot during walking.
Accordingly, in this case the operation is merely mechanical and a stream of inflowing cold air is produced which in winter periods can be particularly unpleasant, since it causes rapid chilling of the feet, causing discomfort to the user.
Moreover, the execution of the pumping devices integrated in the soles is expensive and complicated.
The aim of the present invention is to provide a breathable and waterproof sole for shoes which allows an optimum exchange of heat and water vapor with the outside, which ensures at all times an optimum internal microclimate as a function of the external microclimate, solving the abovementioned drawbacks suffered by known types.
Within this aim, an object of the present invention is to provide a sole in which the integrity of the breathable membrane is protected effectively while allowing adequate air circulation.
Another object is to provide a sole which is able to keep the inside of the shoe dry even in the presence of condensation of the water vapor produced by perspiration due to excessive external humidity.
Another object is to provide a sole which minimizes the problem of deposition of dirty material on the breathable membrane.
Another object is to provide a sole which can be easily adapted to shoes of various kinds both for daily and sports use.
Another object is to provide a sole whose cost is comparable to the costs of known soles.
Another object is to provide a sole which can be manufactured with technologies and equipment which are already known in the field.
This aim and these and other objects which will become better apparent hereinafter are achieved by a breathable and waterproof sole for shoes, characterized in that it comprises, at least along part of its extension:
a lower waterproof component, which constitutes the tread;
an upper component, with a supporting structure which has interconnected chambers with outlets at least on the upper and edge surfaces;
a membrane which is impermeable to water and vapor-permeable and externally surrounds at least the outward-facing regions of said upper component;
said lower and upper components and said membrane being joined so as to form a seal at least in the regions where water infiltration is possible.